Coverage Report

Created: 2024-09-08 06:18

/src/FreeRDP/libfreerdp/primitives/prim_alphaComp.c
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Source (jump to first uncovered line)
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/* FreeRDP: A Remote Desktop Protocol Client
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 * Alpha blending routines.
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 * vi:ts=4 sw=4:
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 *
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 * (c) Copyright 2012 Hewlett-Packard Development Company, L.P.
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 * Licensed under the Apache License, Version 2.0 (the "License"); you may
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 * not use this file except in compliance with the License. You may obtain
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 * a copy of the License at http://www.apache.org/licenses/LICENSE-2.0.
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
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 * or implied. See the License for the specific language governing
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 * permissions and limitations under the License.
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 *
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 * Note: this code assumes the second operand is fully opaque,
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 * e.g.
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 *   newval = alpha1*val1 + (1-alpha1)*val2
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 * rather than
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 *   newval = alpha1*val1 + (1-alpha1)*alpha2*val2
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 */
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#include <freerdp/config.h>
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#include <freerdp/types.h>
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#include <freerdp/primitives.h>
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#include "prim_internal.h"
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#include "prim_alphaComp.h"
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#define ALPHA(_k_) (((_k_)&0xFF000000U) >> 24)
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#define RED(_k_) (((_k_)&0x00FF0000U) >> 16)
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#define GRN(_k_) (((_k_)&0x0000FF00U) >> 8)
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#define BLU(_k_) (((_k_)&0x000000FFU))
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/* ------------------------------------------------------------------------- */
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static pstatus_t general_alphaComp_argb(const BYTE* pSrc1, UINT32 src1Step, const BYTE* pSrc2,
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                                        UINT32 src2Step, BYTE* pDst, UINT32 dstStep, UINT32 width,
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                                        UINT32 height)
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{
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  for (size_t y = 0; y < height; y++)
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  {
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    const UINT32* sptr1 = (const UINT32*)(pSrc1 + y * src1Step);
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    const UINT32* sptr2 = (const UINT32*)(pSrc2 + y * src2Step);
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    UINT32* dptr = (UINT32*)(pDst + y * dstStep);
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    for (size_t x = 0; x < width; x++)
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    {
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      const UINT32 src1 = *sptr1++;
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      const UINT32 src2 = *sptr2++;
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      UINT32 alpha = ALPHA(src1) + 1;
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      if (alpha == 256)
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      {
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        /* If alpha is 255+1, just copy src1. */
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        *dptr++ = src1;
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      }
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      else if (alpha <= 1)
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      {
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        /* If alpha is 0+1, just copy src2. */
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        *dptr++ = src2;
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      }
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      else
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      {
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        /* A perfectly accurate blend would do (a*src + (255-a)*dst)/255
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         * rather than adding one to alpha and dividing by 256, but this
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         * is much faster and only differs by one 16% of the time.
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         * I'm not sure who first designed the double-ops trick
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         * (Red Blue and Alpha Green).
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         */
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        UINT32 rb = 0;
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        UINT32 ag = 0;
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        UINT32 s2rb = src2 & 0x00FF00FFU;
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        UINT32 s2ag = (src2 >> 8) & 0x00FF00FFU;
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        UINT32 s1rb = src1 & 0x00FF00FFU;
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        UINT32 s1ag = (src1 >> 8) & 0x00FF00FFU;
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        UINT32 drb = s1rb - s2rb;
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        UINT32 dag = s1ag - s2ag;
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        drb *= alpha;
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        dag *= alpha;
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        rb = ((drb >> 8) + s2rb) & 0x00FF00FFU;
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        ag = (((dag >> 8) + s2ag) << 8) & 0xFF00FF00U;
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        *dptr++ = rb | ag;
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      }
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    }
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  }
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  return PRIMITIVES_SUCCESS;
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}
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/* ------------------------------------------------------------------------- */
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void primitives_init_alphaComp(primitives_t* prims)
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{
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  prims->alphaComp_argb = general_alphaComp_argb;
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1
}
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void primitives_init_alphaComp_opt(primitives_t* WINPR_RESTRICT prims)
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{
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  primitives_init_alphaComp_sse3(prims);
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}